1. Field of the Invention
The present invention relates to a cryogenic regenerator that uses helium gas as a regenerator material and a method of manufacturing such a cryogenic regenerator.
2. Description of the Related Art
In general, Gifford-McMahon (GM) cryocoolers, pulse tube cryocoolers, Stirling cryocoolers, and Solvay cryocoolers, for example, are known as cryocoolers that include regenerators. The regenerators included in these cryocoolers are configured to cool refrigerant gas that flows toward an expansion chamber, for example, and accumulate cold generated by the refrigerant gas when the refrigerant gas passes through the regenerator. That is, by including a regenerator, the cooling effect of the cryocoolers may be improved.
In a case where a cryogenic temperature of less than or equal to 30 K, for example, has to be generated at the cryocooler, selecting a regenerator material that has high specific heat (volume specific heat) at this temperature may contribute to improvement of the cooling effect.
For example, the regenerator disclosed in Japanese Unexamined Patent Publication No. 63-054577 has a band-like hollow structure wound around a regenerator body that is configured to have helium gas sealed therein. One end of the band-like hollow structure is sealed, and the other end of the band-like hollow structure is connected to a buffer tank that has a capacity of about 500-1000 times the capacity of the band-like hollow structure and is filled with helium gas. In this way, the disclosed regenerator is configured to retain the pressure of helium gas under a cryogenic temperature.